In all previous signal amplifying methods, for low and high frequencies there are lots of disadvantages and problems such as low efficiency, large circuit size, high costs, limited bandwidth and etc. All the above mentioned disadvantages creates complexity in the design, time consuming procedure and high costs. In fact every method has its own limitations and these limitations prevent a designer not to reach the ideal point (such as high bandwidth, high efficiency, simplicity in design, smaller size . . . ). Amplifiers are categorized in different classes. Current common amplifiers work in A/B/AB/C/D/E/F classes.